In FIG. 1, a turret punch press 501 serving as a punch press which is conventionally well-known is shown. The turret punch press 501 is provided in a standing manner with a frame 503 having a gap portion G at a central portion thereof, and an upper portion turret 505U which is supported at an upper portion frame 503U in a rotationally indexable manner and is equipped with a plurality of punches P is provided at the gap portion G. Further, a lower portion turret 505L which is equipped with a plurality of dies D (refer to FIG. 2 to FIG. 5) is provided in a rotationally indexable manner on a lower portion frame 503L so as to opposed to the upper portion turret 505U. The upper portion turret 505U and the lower portion turret 505L are rotated synchronously by a driving mechanism such as a rotating belt 509 rotated by a motor 507 or the like.
Further, a working table 511 which movably supports a workpiece W is provided at the gap portion G. A carriage base 519 which can be moved and positioned in a Y-axis direction via a Y-axis ball nut 517 according to rotation of a Y-axis ball screw 515 performed by a Y-axis motor 513. An X carriage 521 which can be moved and positioned in an X-axis direction is provided on the carriage base 519, and workpiece clampers 523 for clamping a workpiece W are provided on the X carriage 521 such that an interval therebetween is adjustable.
Incidentally, a hydraulic unit 525 for driving a driving apparatus, an NC console 527 for controlling positioning of a workpiece W or rotational indexing of the upper portion turret 505U and the lower portion turret 505L, or the hydraulic unit 525, and the like are provided in the vicinity of the turret punch press 501.
With the above constitution, the upper portion turret 505U and the lower portion turret 505L are rotated to index the punch P and the die D to be used to a working position K, and the carriage base 519 is moved in the Y-axis direction and the X carriage 521 is moved in the X-axis direction, so that a working point in the workpiece W clamped by the workpiece clampers 523 is indexed to the working position K. Then, the punch P is actuated in a punching manner by an unillustrated driving apparatus so that a punching working is performed in cooperation of the punch P and the die D.
However, as shown in FIG. 2, in the above-described turret punch press 501, since a feed clear d between the upper portion turret 505U and the lower portion turret 505L is small (for example, 20 mm), there is a possibility that in a working where a warp occurs in a workpiece W, the workpiece W is caught by dies equipped in the upper and lower portion turrets 505U, 505L so that the workpiece W is crushed.
As shown in FIG. 3, also, since it is difficult to move all the dies D equipped on the lower portion turret 505L synchronously in a vertical direction at a time of movement of a workpiece W, there is a problem that a back face of the workpiece W is injured by a die D equipped on the lower portion turret 505L.
Furthermore, in case of using the turrets 505U, 505L, since a plurality of dies AAA are arranged on a pass line, a formed portion 529 of a workpiece W interferes with an adjacent punch and die set to be crushed or injured in case that a forming work, and particularly a downward forming work is conducted on the workpiece W, as shown in FIG. 4. For this reason, since the downward forming is particularly conducted in another step, or such a movement or working order that the interference can be avoided is edited manually by devising a program, there is a problem that a working efficiency is lowered due to occurrence of a skilled work required.
That is, in an automatic programming apparatus, a movement locus is determined such that a working time, namely a material movement distance to the next working coordinates is made shortest, but it becomes impossible to automate a program, because such a movement locus that a problem of a catching or the like can be solved can not be considered.
Further, as shown in FIG. 5, in the turret punch press 501, since a relief clearance is provided such that a punched-out scrap is not caught by a disc support 531 supporting the lower portion turret 505L from its lower side at a time of working, there is a problem that the punched-out material can not be sucked effectively.
Moreover, in case that indexing functions for angular direction of each punch and die set (auto-indexes) are provided on the upper and lower portion turrets 505U, 505L, there is a problem that parts such as a worm gear for indexing and the like increases, which makes the turret punch press 501 expensive. Further, since a space is occupied by the gear or the like, the number of punch and die set stations is largely reduced (to about a half of the number), which causes a case that the working can not be conducted unless punch and die set exchanging is performed. As a result, there is a problem that productivity reduction is caused.
In order to solve these various problems, a punch press with a NC of a single head constitution where the punch P and the die D are mounted in one press mechanism is also used without using the upper and lower portion turrets 505U, 505L.
However, in the above-described turret punch press 501, there are various problems but there is a large advantage that a plurality of dies can be held and a punch and die set selection time is short (usually, 3 seconds or less) owing to use of the upper and lower turrets 505U, 505L so that a high productivity can be achieved. On the other hand, since only one punch and die set is usually held in the single head constitution, there is a problem that die exchange must frequently be performed in a sheet working of a plate metal using a plurality of dies.
For this reason, a punch and die set called a multi-tool where a plurality of dies are equipped in one punch and die set is also used, but since the punch and die set is constituted such that other dies are built in one punch and die set, there is a problem that dies other than a punch and die set having a small size can not be equipped.
Further, in case that one punch and die set in the multi-tool is selected according to a program and there is not a punch and die set to be used next in the multi-tool, the punch and die set must be exchanged to another punch and die set, which is not so effective for reduction of a punch and die set exchanging time.
Furthermore, the multi-tool is estimated high regarding a point that the number of held punch and die sets is increased. However, since workpiece dampers can not be moved near a punch and die set due to a relationship where dies with a small size have been structurally equipped in one main punch and die set frame, there is a defect that a region which can not be worked (a dead zone) increases, and there is a problem that the dead zone restrains a program, which makes it difficult to use the multi-tool in a real working.
On the other hand, in the single head constitution, since one punch and die set is merely held usually, a punch and die set accommodating apparatus accommodating a plurality of dies is required in a sheet working of a plate metal using a plurality of dies, in which there is a problem that a punch and die set accommodating apparatus which accommodates many dies is required, which results in large-sizing of the apparatus. Moreover, since dies must frequently be exchanged, there is a problem that working efficiency is reduced.
The present invention has been made in order to solve the above-described problems, and a first object thereof is to provide a punch press which can perform punch and die set exchanging rapidly and a punch/die exchanging method for a punch press.
A second object of the present invention is to provide a punch system which can accommodate many dies and can perform efficient punching work by conducting punch and die set exchanging rapidly.